While a hydrocarbon well is often no more than a foot in diameter, overall operations at an oilfield may be quite massive. For example, stimulation operations at an oilfield may include fracturing applications that utilize 10-20 or more multiplex pumps with dedicated engines. These pumps and engines may act in concert through a manifold to drive a fracturing fluid at high pressure into the well. In this way fractures may be formed and propped open with hydrocarbon production being encouraged as a result. Specifically, the fractures may then serve as channels through the formation through which hydrocarbons may reach the wellbore. The indicated fracturing fluid generally includes a solid particulate referred to as proppant, often sand. The proppant may act to enhance the formation of fractures during the fracturing operation and may also remain primarily within fractures upon their formation.
Setting aside the massive amount of equipment placed at the oilfield for such operations, the pumps and even more so the engines for the pumps may present a sizeable noise issue for operators and areas around the oilfield. For example, in such operations, the pumps and engines generally operate continuously for several hours at a time. Further, during operations, each engine may emit in excess of about 75-100 dB. As described below, this level of audible noise may be hazardous to operators on site and present a nuisance to communities and areas adjacent the oilfield.
Direct exposure to more than 85 dB for any extended period of time is generally considered a health hazard. However, as a practical matter, it is not possible to restrict operator access to the oilfield throughout such stimulation operations. That is, a regular need to access pumps, engines and other nearby equipment for sake of minor tool adjustments, monitoring and other manual inspections is necessary. Once more, it would not be practical to shut down operations each time the need for such an adjustment or inspection presented itself. Thus, it is quite common for operators to spend time on site in a generally noise-proof trailer and then put on ear safety equipment when the need arises for leaving the trailer.
Unfortunately, ear safety equipment is far from full proof. For example, commonly available ear muffs and plugs are only effective when worn. That is, the possibility of the operator wearing such personal protection requires affirmative compliance by the operator. If an operator loses, breaks, or just forgets his or her ear safety equipment when leaving the trailer, he or she may be exposed to hazardous levels of noise. Once more, even when worn, another issue is presented. Namely, whether due to engine noise or ear protection, audible communication with the operator is compromised whenever the operator is present at the oilfield with engines running as described above. Thus, compromised communications which limit safe instruction and forewarning to operators may lead to increased risk of injury regardless of, and perhaps even due to, proper use of ear safety equipment.
With ear protection limitations in mind, additional efforts are generally undertaken to limit or “muffle” the amount of noise emitted from engines during operations. Specifically, pump engines are generally each outfitted with conventional industrial mufflers. For a standard diesel engine suitable for driving an oilfield multiplex pump, this may cost-effectively reduce noise output to below about 85 dB. However, this is generally not considered sufficient enough of a reduction to allow operators to safely forego ear protection for an extended period. Once more, this level of noise reduction also fails to fully eliminate the audible nuisance presented to areas adjacent the oilfield that are still faced with the running of multiple diesel engines on an ongoing basis.
With these remaining issues in mind, conventional industrial mufflers may be replaced with substantially larger hospital grade mufflers. In this way, noise may be substantially reduced to well below 80 dB at each engine. Unfortunately, however, these types of mufflers are substantially larger and more costly than those of the conventional variety. Specifically, these mufflers may drive up engine equipment expenses by about 20% and add an extra 400-500 lbs. or more to each engine. Once more, in conjunction with the added effort required to move and manage the added load, the associated skid or mobile platform for the pump and engine may require some modification to accommodate the increased equipment size.
The added challenge of utilizing a heavier and more expensive muffler is magnified depending on the number of dedicated pumps and pump engines utilized at the oilfield. That is, recalling that the operations may employ 10-20 or more pumps, the total challenge grows as the number of pumps utilized grows. In terms of dollars alone, an added $3,000 may be expected per hospital grade muffler. Thus, the increase may be $30,000-$60,000 or more in added expense depending on the particular operation setup. Furthermore, even where utilized, the reduction in noise is unlikely to be so dramatic as to eliminate all nuisance noise with respect to areas adjacent the oilfield during operations.